Nghi Co Nguyen MD, PhD, Abstract Co-Author: Research Grant, Koninklijke Philips NV

Jose Luis Vercher-Conejero MD, Abstract Co-Author: Fellowship funded, Koninklijke Philips NV

James K. O'Donnell MD, Abstract Co-Author: Research support, Koninklijke Philips NV Research support, Eli Lilly and Company Speakers Bureau, Astellas Group Speakers Bureau, Bayer AG Advisory Board, Eli Lilly and Company Advisory Board, Navidea Biopharmaceuticals, Inc

Abdus Sattar PhD, Abstract Co-Author: Research collaboration, Koninklijke Philips NV

Peter F. Faulhaber MD, Presenter: Speaker, Koninklijke Philips NV Grant, Koninklijke Philips NV Medical Advisor, MIM Software Inc

We present our initial clinical experience for a digital PET prototype equipped with photon counting detectors and Time-of-flight technology (DigitalTF) developed by Philips Healthcare and compared the diagnostic performance with an analog PET with Time-of-flight (Gemini TF, Philips).

Twenty-one patients (pts) - age 58 ± 15; 7 lung & 4 breast cancers, 2 lymphoma; 2 H&N cancer, 6 other tumors – first underwent clinical FDG PET/CT on the GeminiTF. The scanner table was then withdrawn, the DigitalTF ring was inserted between the GeminiTF PET and CT scanner, and the pt was scanned for a second time with 22 ± 12 min scan delay, using the same PET FOV with CT from GeminiTF for attenuation correction. Two experienced readers reviewed the two PET scans separately for image quality using a 4-point scale. Subsequently, they compared the two data sets side-by-side for diagnostic confidence on a 5-point scale and made note of differences in the lesion detectability as well as TNM staging (6 of 21 pts), all blinded to the scanner type; the readers were aware of the clinical indication for PET/CT. Discordant cases of lesion detectability and TNM staging were resolved by consensus between the two readers. Histopathology and imaging findings in medical record served as reference standards. Wilcoxon tests, and regression analyses to estimate average scores were used.

DigitalTF scored better in image quality [median 4.0 (3.0-4.0) vs. 3.5 (3.0-4.0)] and diagnostic confidence (mean 3.5±0.8) compared with GeminiTF, p<0.05. In all 21 pts, DigitalTF detected additional 9 lesions in 6 of 21 pts (29%) compared to GeminiTF; median size was 0.6 cm (range 0.5-0.9) with lesion SUVmax 1.5 (range 1.4-3.5) vs. 1.3 (range 0.8-2.3), p < 0.05. In 15 restaging pts, the true positive rate was 100% (7 pts), the true negative rate 75% (6 of 8 pts) and the false negative rate 25% on per-patient basis for both modalities. In 6 pts with initial diagnosis or staging, DigitalTF lead to an upstaging in 2 pts (33%) compared with GeminiTF; staging was the same in the remaining 4 pts.

DigitalTF is a promising technology that has to potential to improve diagnostic confidence and accuracy in oncologic diseases compared with GeminiTF.

Digital PET with photon counting detectors and time-of-flight capability has the potential improve not only image quality but also diagnostic confidence and accuracy in oncologic diseases.  

Nguyen, N, Vercher-Conejero, J, O'Donnell, J, Sattar, A, Faulhaber, P, Diagnostic Performance of a Digital PET Prototype in Patients with Oncologic Diagnosis: Initial Clinical Experience and Comparison with Analog PET.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14007879.html